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<H1>/(+Number1, +Number2, -Result)</H1>
Evaluates the quotient Number1 / Number2 and unifies the resulting value
with Result.


<DL>
<DT><EM>Number1</EM></DT>
<DD>A number.
</DD>
<DT><EM>Number2</EM></DT>
<DD>A number.
</DD>
<DT><EM>Result</EM></DT>
<DD>A variable or float (resp. rational).
</DD>
</DL>
<H2>Description</H2>
   This predicate is used by the ECLiPSe compiler to expand evaluable
   arithmetic expressions.  So the call to /(Number1, Number2, Result) is
   equivalent to
<PRE>
    Result is Number1 / Number2
</PRE>
    which should be preferred for portability.
<P>
   The result type of the division depends on the value of the global flag
   prefer_rationals.  When it is off, the result is a float,
   when it is on, the result is a rational.  In coroutining mode, if
   Number1 or Number2 are uninstantiated, the call to //3 is delayed until
   these variables are instantiated.

<P>

<H3>Modes and Determinism</H3><UL>
<LI>/(+, +, -) is det
</UL>
<H3>Exceptions</H3>
<DL>
<DT><EM>(4) instantiation fault </EM>
<DD>Number1 or Number2 is not instantiated (non-coroutining mode    only).
<DT><EM>(24) number expected </EM>
<DD>Number1 or Number2 is not of a numeric type.
<DT><EM>(20) arithmetic exception </EM>
<DD>Illegal arithmetic operation:  division by 0
</DL>
<H2>Examples</H2>
<PRE>
Success:
    /(10, 2, 5.0).
    /(10, -2.0, -5.0).
    /(9, 12, 3_4).      (with set_flag(prefer_rationals, on))
Fail:
    /(1, 2, 1.0).
    /(5, 2, r).
    /(6, 2, 3).
Error:
    /(A, 2, 6.0).            (Error 4).
    /(2, 0, Result).         (Error 20).
    /(4 + 2, 2, 12).         (Error 24).



</PRE>
<H2>See Also</H2>
<A HREF="../../kernel/arithmetic/is-2.html">is / 2</A>, <A HREF="../../kernel/env/get_flag-2.html">get_flag / 2</A>, <A HREF="../../kernel/env/set_flag-2.html">set_flag / 2</A>
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